The present invention relates to a complete swivel type backhoe vehicle or excavator comprising a chassis including right and left traveling devices, an upper carriage swivellable 360 degrees on the chassis and an excavating assembly attached to the upper carriage to be pivotable on a vertical axis, wherein the excavating assembly in a contained position is located in a locus circle described by an outer contour of the upper carriage.
A conventional backhoe vehicle of this type is known, for example, from European patent laying-open publication No. 0 131 939 A1. The backhoe vehicle disclosed in this publication has an excavating assembly holder located at a laterally displaced position on the front end of the upper carriage. The excavating assembly as folded up is erected to a limit and is brought close to a swivel axis of the upper carriage by pivoting the excavating assembly until a side face of the bucket lies close to a front end of the driver's section. This operation permits the excavating assembly to lie within a locus circle described by an outer contour of the upper carriage.
However, the foldup position of the excavating assembly as described above allows only a very limited range of choice for positioning of a pivotal connection between the excavating assembly holder and a cylinder for raising and lowering the boom. More particularly, where the position of the pivotal connection between the excavating assembly holder and the boom raising and lowering cylinder is selected in order to be capable of digging a deepest possible trench with a given excavating assembly, the excavating assembly does not come close enough to the vehicle even when the boom is raised to a limit. This is inconvenient for swivelling purposes.
In order to solve this problem, two pivotal connections may be provided for the excavating assembly holder and the boom raising and lowering cylinder, one of the connections being at a position to permit the excavating assembly to approach the swivel axis of the upper carriage as much as possible and the other connection at a position suited for deep excavation. This modification, however, has the following disadvantage.
It is necessary for the boom to have a good degree of bend at its bent portion in order to achieve a great digging depth. However, when the boom is raised, the back of such a bent portion protrudes into a space in the driver's section as shown in a phantom line in FIG. 1 of the accompanying drawings. This not only reduces the accommodating space for the driver but is dangerous to the driver. Therefore, the above modification is satisfactory to a limited degree only.